Is it possible using Bitmap.Save to produce a GIF file that is 4bpp?

Seems that I always get 8bpp.

If I know it's not possible I'll quit trying.


Thanx

> Is it possible using Bitmap.Save to produce a GIF file that is 4bpp?


Neither the gdi+ gif encoder nor the WIC gif encoder will create a 4bpp gif 
file.

""Frank""  wrote in message 
news:uevFjp$4HHA.6024@TK2MSFTNGP05.phx.gbl...

> Is it possible using Bitmap.Save to produce a GIF file that is 4bpp?
>
> Seems that I always get 8bpp.
>
> If I know it's not possible I'll quit trying.
>
>
> Thanx
>
>
> 

that explains a lot.

I don't image there is a free encoder that does. Is there?

thanks

"Michael Phillips, Jr." <mphillips53@nospam.jun0.c0m> wrote in message 
news:uYfxjdB5HHA.3916@TK2MSFTNGP02.phx.gbl...

>> Is it possible using Bitmap.Save to produce a GIF file that is 4bpp?
>
> Neither the gdi+ gif encoder nor the WIC gif encoder will create a 4bpp 
> gif file.
>
> ""Frank""  wrote in message 
> news:uevFjp$4HHA.6024@TK2MSFTNGP05.phx.gbl...
>> Is it possible using Bitmap.Save to produce a GIF file that is 4bpp?
>>
>> Seems that I always get 8bpp.
>>
>> If I know it's not possible I'll quit trying.
>>
>>
>> Thanx
>>
>>
>>
>
> 

"Michael Phillips, Jr." <mphillips53@nospam.jun0.c0m> wrote in message 
news:ueIBYOD5HHA.5360@TK2MSFTNGP03.phx.gbl...

>> I don't image there is a free encoder that does. Is there?
>
> I do not know of any.   You can still create an 8bpp gif with a reduced 
> color table with the current encoder.
>

How do I do that?

> How do I do that?


Use the quantization color reduction algorithm to reduce a palette and 
assign it to your gif.

The algorithm's code is available on MSDN.  Bob Powell' site has code to 
work with gif palettes.

Find great Windows Forms articles in Windows Forms Tips and Tricks
http://www.bobpowell.net/tipstricks.htm

Answer those GDI+ questions with the GDI+ FAQ
http://www.bobpowell.net/faqmain.htm

""Frank""  wrote in message 
news:ezBe4xJ5HHA.5844@TK2MSFTNGP02.phx.gbl...

>
> "Michael Phillips, Jr." <mphillips53@nospam.jun0.c0m> wrote in message 
> news:ueIBYOD5HHA.5360@TK2MSFTNGP03.phx.gbl...
>>> I don't image there is a free encoder that does. Is there?
>>
>> I do not know of any.   You can still create an 8bpp gif with a reduced 
>> color table with the current encoder.
>>
> How do I do that?
>
>
> 

I found that.
There is also on the Internet that has been modified to remove the "Unsafe" 
statement.
It's really the same code line by line except some of the statement have 
been modified.

In a GIF file there is a value for "Color Resolution"
"Number of bits per primary color available to the original image... "

I see values like 10 and 13.

What is that. I read the sentence but don't understand what it means unless 
it means a color required 30 or 39 bits.
And what does "original image" mean

Thanks for pointing out the color reduction algorithm.



"Michael Phillips, Jr." <mphillips53@nospam.jun0.c0m> wrote in message 
news:%230f9M5L5HHA.3900@TK2MSFTNGP02.phx.gbl...

>> How do I do that?
>
> Use the quantization color reduction algorithm to reduce a palette and 
> assign it to your gif.
>
> The algorithm's code is available on MSDN.  Bob Powell' site has code to 
> work with gif palettes.
>
> Find great Windows Forms articles in Windows Forms Tips and Tricks
> http://www.bobpowell.net/tipstricks.htm
>
> Answer those GDI+ questions with the GDI+ FAQ
> http://www.bobpowell.net/faqmain.htm
>
> ""Frank""  wrote in message 
> news:ezBe4xJ5HHA.5844@TK2MSFTNGP02.phx.gbl...
>>
>> "Michael Phillips, Jr." <mphillips53@nospam.jun0.c0m> wrote in message 
>> news:ueIBYOD5HHA.5360@TK2MSFTNGP03.phx.gbl...
>>>> I don't image there is a free encoder that does. Is there?
>>>
>>> I do not know of any.   You can still create an 8bpp gif with a reduced 
>>> color table with the current encoder.
>>>
>> How do I do that?
>>
>>
>>
>
> 

> In a GIF file there is a value for "Color Resolution"
> "Number of bits per primary color available to the original image... "


Red , Green , Blue colors represented as bit values such as 555, 565, 888, 
etc. where the value specifies the number of bits in that color's channel.

The higher the bit value the greater the color resolution.


> And what does "original image" mean


The algorithm creates a palette that best represents the colors in the 
original image.

The original image has more colors available than is possible to fit in a 
palette so the number of colors needs to be reduced.


""Frank""  wrote in message 
news:%23xu84AV5HHA.4928@TK2MSFTNGP05.phx.gbl...

>I found that.
> There is also on the Internet that has been modified to remove the 
> "Unsafe" statement.
> It's really the same code line by line except some of the statement have 
> been modified.
>
> In a GIF file there is a value for "Color Resolution"
> "Number of bits per primary color available to the original image... "
>
> I see values like 10 and 13.
>
> What is that. I read the sentence but don't understand what it means 
> unless it means a color required 30 or 39 bits.
> And what does "original image" mean
>
> Thanks for pointing out the color reduction algorithm.
>
>
>
> "Michael Phillips, Jr." <mphillips53@nospam.jun0.c0m> wrote in message 
> news:%230f9M5L5HHA.3900@TK2MSFTNGP02.phx.gbl...
>>> How do I do that?
>>
>> Use the quantization color reduction algorithm to reduce a palette and 
>> assign it to your gif.
>>
>> The algorithm's code is available on MSDN.  Bob Powell' site has code to 
>> work with gif palettes.
>>
>> Find great Windows Forms articles in Windows Forms Tips and Tricks
>> http://www.bobpowell.net/tipstricks.htm
>>
>> Answer those GDI+ questions with the GDI+ FAQ
>> http://www.bobpowell.net/faqmain.htm
>>
>> ""Frank""  wrote in message 
>> news:ezBe4xJ5HHA.5844@TK2MSFTNGP02.phx.gbl...
>>>
>>> "Michael Phillips, Jr." <mphillips53@nospam.jun0.c0m> wrote in message 
>>> news:ueIBYOD5HHA.5360@TK2MSFTNGP03.phx.gbl...
>>>>> I don't image there is a free encoder that does. Is there?
>>>>
>>>> I do not know of any.   You can still create an 8bpp gif with a reduced 
>>>> color table with the current encoder.
>>>>
>>> How do I do that?
>>>
>>>
>>>
>>
>>
>
>